Method, apparatus and system for use in dental procedures

ABSTRACT

A method and system are provided for providing patient data useful for dental procedures, including scanning a dental structure of a patient when coupled to a geometric structure to provide a virtual model representative of the coupling and the dental structure, and relating the virtual model to a body reference of the patient.

CROSS-REFERENCE

This application is a continuation of U.S. patent application Ser. No.14/051,754, filed Oct. 11, 2013, now U.S. Pat. No. 10,524,886, issuedJan. 7, 2020, which is a continuation of U.S. patent application Ser.No. 12/451,896, filed Dec. 4, 2009, now U.S. Pat. No. 9,408,679, issuedAug. 9, 2016, which is a U.S. National Phase Application under 35 U.S.C.§ 371 of International Application No. PCT/IL2009/000662, filed on Jul.2, 2009, which claims the benefit of U.S. Provisional Application No.61/129,553, filed Jul. 3, 2008, and U.S. Provisional Application No.61/193,071, filed Oct. 27, 2008, the entire contents of each of whichare hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

This invention relates to dental data and dental procedures, inparticular with reference to apparatuses, systems and methods associatedwith dental data and dental procedures, in particular dentalarticulation and dental restorations.

BACKGROUND OF THE INVENTION

Articulators are well known dental devices which attempt to replicatethe movement of the lower jaw relative to the upper jaw about theTemporomandibular Joint (TMJ) in a patient-specific manner. Typically,plaster models of the patient's upper and lower teeth arches are mountedto the articulator with respect to its hinge axis in a manner simulatingthat of the real teeth arches with respect to the patient's TMJ joint.Traditionally, physical impressions of the dental arches are provided,which are then used for casting the plaster models. In addition, a biteimpression is obtained with a wax bite plate, which records the relativepositions of the upper and lower arches.

A mechanical facebow with a bite fork is often used for obtainingpatient-specific measurements which are then used to set up the plastermodel in a particular articulator. In particular, the spatialorientation of the patient's maxillary arch with respect to the earcanals is duplicated by the facebow. The facebow is engaged to the earcanals via an ear canal insertion portion. Then, a bite fork withimpression material is brought into engagement with the maxillary teeth,and a jig connects the bite fork via its arm to the facebow. The facebowand bite fork combination are then mechanically rigidly coupled to thearticulator, such that the ear canal insertion portions are in thecorresponding alignment with the pivot axis of the articulator. Theplaster models are mounted to the articulator so as to engage and thusmatch the position of the bite fork, and plaster filling is providedbetween each plaster model and the respective articulator arm. However,this is a complicated and time consuming process, and which requiresexpert handling. Once the models are mounted, the facebow and bite forkcan be removed.

The articulator mounted with the plaster models can be made use of for alarge number of orthodontic, prosthodontic and other dentalapplications. For example, dental restoration procedures often make useof articulators to design and test prostheses before implantation in apatient.

By way of general background, U.S. Pat. No. 6,152,731 discloses acomputer implemented method that includes providing a first set ofdigital data corresponding to an upper arch image of at least a portionof an upper dental arch of a patient, providing a second set of digitaldata corresponding to a lower arch image of at least a portion of alower dental arch of the patient, providing bite alignment datarepresentative of the spatial relationship between the upper dental archand the lower dental arch of the patient, and aligning the upper andlower arch images relative to one another based on the bite alignmentdata until an aligned upper and lower arch image is attained. Thealigned upper and lower arch images are moved towards each other until afirst contact point is detected and at least one of the upper and lowerarch images is moved relative to the other in one or more directions toa plurality of positions for determining optimal occlusion position ofthe lower and upper dental arches.

SUMMARY OF THE INVENTION

The term “virtual model” is used herein synonymously with “numericalentity”, 3D model, computer generated model, and other such terms, andrelates to a virtual representation in a computer environment of a real(physical) object, for example a dentition or part thereof or at least apart of intraoral cavity, or of a real (physical) model thereof, forexample.

The term “scanning” and its analogues refer to any procedure directed atobtaining 3D topographic data of a surface, particularly of a dentalsurface, and thus includes: mechanical or contact methods, typicallybased on 3D probes for example; non-contact methods, in particularoptical methods, including for example confocal methods, for example asdisclosed in WO 00/08415, the contents of which are incorporated hereinin their entirety by reference; or indeed any other suitable method. Theterm “scanner” refers to any suitable device or system that provides ascanning operation.

The term “display” and its analogues refer to any means or method fordelivering a presentation, which may include any information, data,images, sounds, etc, and thus the delivery may be in visual and/or audioform, for example an electronic audio/visual image, printed matter, andso on.

While the term “dental structure” herein is taken to include, inaddition to a patient's dentition or part thereof or, including part ofa tooth, including a preparation, a tooth or a number of teeth, or oneor both dental arches, dental restorations or prostheses, or at least apart of the intraoral cavity, it is also taken to include a real(physical) model of part of a tooth, including a preparation, a tooth ora number of teeth, or one or both dental arches, dental restorations orprostheses, or at least a part of the intraoral cavity, for example, thereal model being a positive model, or a negative model (impression) or acomposite positive-negative model.

According to a first aspect of the invention there is provided a methodfor providing a spatial relationship of at least part of a dentalstructure of a patient with respect to a body reference of the patient,comprising

-   -   (a) generating a first virtual model representative of at least        a part of said dental structure coupled with a geometric        structure in a first spatial relationship therewith, wherein a        second spatial relationship between said geometric structure and        said body reference is known or determinable;    -   (b) determining the spatial relationship between said part of        said dental structure and said body reference from said first        spatial relationship and said second spatial relationship.

The term “geometric structure” is used interchangeably herein with“geometrical structure”, and includes any suitable structure having ageometric form that is substantially fixed in geometry and exposed inconjunction with the part of a dental structure, at least whenimplementing, said method.

The method at least according to the first aspect of the invention, mayoptionally further comprise one or more of the following features in anysuitable combination.

In some embodiments, step (a) comprises scanning said part of saiddental structure coupled with said geometric structure with a suitablescanner to obtain said first virtual model. In other embodiments, saidgeometric structure further comprises a physical impression of said partof said dental structure, and step (a) comprises scanning saidimpression coupled with said geometric structure with a suitable scannerto obtain a second virtual model, and generating said first virtualmodel from said second virtual model; step (a) may comprise providing athird virtual model representative of said part of said dentalstructure, and registering said third virtual model with said secondvirtual model and generating therefrom said first virtual model.

The method may further comprise providing a virtual model of a seconddental structure that includes said part of said first-mentioned dentalstructure, registering said virtual model of said second dentalstructure with said first virtual model, and determining the spatialrelationship between said second dental structure and said bodyreference from said first spatial relationship, said second spatialrelationship.

The scanner may comprise, for example, an optical scanner, andoptionally operation of said scanner is based on confocal imagingtechniques. For example, the scanner may comprise:

-   -   a probing member with a sensing face;    -   first illumination means for providing a first array of incident        light beams transmitted towards the structure along an optical        path through said probing unit to generate illuminated spots on        said portion along said depth direction, wherein said first        array is defined within said reference array;    -   a light focusing optics defining one or more focal planes        forward said probing face at a position changeable by said        optics, each light beam having its focus on one of said one or        more focal plane;    -   a translation mechanism for displacing said focal plane relative        to the structure along an axis defined by the propagation of the        incident light beams;    -   a first detector having an array of sensing elements for        measuring intensity of each of a plurality of light beams        returning from said spots propagating through an optical path        opposite to that of the incident light beams;    -   a processor coupled to said detector for determining for each        light beam a spot-specific position, being the position of the        respective focal plane of said one or more focal planes yielding        maximum measured intensity of the returned light beam, and based        on the determined spot-specific positions, generating data        representative of the topology of said portion

In at least some embodiments, the body reference may be at least one ofthe ear canals, including an axis coaxial and through the two ear canalsof the patient, and/or the TMJ of the patient. Step (a) may include:

-   -   providing said geometric structure in the form of a facebow        apparatus having a first facebow part coupled to a second        facebow part via a coupling, such as a mechanical coupling for        example, that enables the spatial relationship between the first        facebow part and the second facebow part to be selectively        adjusted,    -   setting said first facebow part in a fixed spatial relationship        with respect to said part of said dental structure to define        said first spatial relationship, and    -   setting said second facebow part in a fixed first facebow        spatial relationship with respect to said body reference and in        a fixed second facebow spatial relationship with respect to said        first facebow part via said coupling to define said second        spatial relationship.

In other words, step (a) may include:

-   -   providing said geometric structure in the form of a facebow        apparatus having a first facebow part coupled to a second        facebow part via a coupling, such as a mechanical coupling for        example, that enables the spatial relationship between the first        facebow part and the second facebow part to be selectively        adjusted,    -   coupling the facebow apparatus to said part of said dental        structure by setting said first facebow part in a fixed spatial        relationship with respect to said part of said dental structure        to define said first spatial relationship, and    -   manipulating said second facebow part with respect to said first        facebow part via said coupling thereby setting said second        facebow part in a fixed first facebow spatial relationship with        respect to said body reference and in a fixed second facebow        spatial relationship with respect to said first facebow part via        said coupling to define said second spatial relationship.

The said first facebow part may be in the form of a bite fork apparatus,for example, and comprises a bite plate mounted to said coupling, andsaid coupling may be configured for providing at least two degrees offreedom for said bite plate with respect to said second facebow part,which operates substantially as a rigid body with respect to saidcoupling, wherein step (a) comprises manipulating said first facebowpart with respect to said second facebow part via said coupling untilsaid bite plate is abutted to at least one tooth arch of the patientcomprising said part of said dental structure, while concurrentlysetting said second facebow part at fixed said first facebow spatialrelationship with respect to said body reference. In at least oneexample, said degrees of freedom include a translation and a rotation ofsaid bite plate with respect to said second facebow part. In at leastanother example, said degrees of freedom include a first rotation, asecond rotation, and a rotation of said bite plate with respect to saidsecond facebow part, and said first rotation and said second rotationmay comprise respective rotational axes that are mutually orthogonal.

Step (a) may comprise generating a virtual model of a first zone of saidfacebow apparatus comprising at least a portion of said couplingsufficient to indicate the relative position and orientation of saidbiteplate with respect to said second facebow part, and providing aspatial relationship between said body reference and said coupling, anddetermining said second facebow spatial relationship from said firstzone virtual model and said spatial relationship between said bodyreference and said coupling. The said first zone virtual model may begenerated by scanning said first zone with said scanner or with anothersuitable scanner. The second facebow spatial relationship may comprise ageometrical relationship including a position and orientation of saidcoupling with respect to a facebow reference axis associated with saidsecond facebow portion, wherein in step (a) said facebow reference axisis aligned with the ear canals or the patient or the TMJ of the patient.

Said spatial relationship between said body reference and said couplingmay be provided by scanning sufficient portions of the second facebowportion to enable reconstruction of a virtual model thereof, sufficientto define said spatial relationship between said body reference and saidcoupling.

Alternatively, step (a) may comprise generating at least a first partialvirtual model of a first zone of said facebow apparatus comprising saidpart of said dental structure and a portion of said biteplate coupledthereto, and generating a second partial virtual model of a second zoneof said facebow apparatus comprising at least a portion of said couplingsufficient to indicate the relative position and orientation of saidbiteplate with respect to said second facebow part, and determining saidsecond facebow spatial relationship from said first and second partialvirtual models. The said first partial virtual model and said secondpartial virtual model are generated by respectively scanning said firstzone and said second zone with said scanner or with another suitablescanner. The second facebow spatial relationship may comprise ageometrical relationship including a position and orientation of saidcoupling with respect to a facebow reference axis associated with saidsecond facebow portion, wherein in step (a) said facebow reference axisis aligned with the ear canals or the patient or the TMJ of the patient.

In at least some embodiments, the body reference is a midsagittal planeof the patient. Step (a) may include:

-   -   providing said geometric structure in the form of a biteplate        apparatus having a first biteplate part coupled to a second        biteplate part via a coupling that enables an orientation        between the first biteplate part and the second biteplate part        to be selectively adjusted,    -   setting said first biteplate part in a fixed spatial        relationship with respect to said part of said dental structure        to define said first spatial relationship, and    -   setting said second biteplate part in a fixed first biteplate        spatial relationship with respect to said body reference and in        a fixed second biteplate spatial relationship with respect to        said first biteplate part via said coupling to define said        second spatial relationship.

In other words, step (a) may include:

-   -   providing said geometric structure in the form of a biteplate        apparatus having a first biteplate part coupled to a second        biteplate part via a coupling that enables an orientation        between the first biteplate part and the second biteplate part        to be selectively adjusted,    -   coupling the biteplate apparatus to said part of said dental        structure by setting said first biteplate part in a fixed        spatial relationship with respect to said part of said dental        structure to define said first spatial relationship, and    -   manipulating said second biteplate part with respect to said        first biteplate part via said coupling thereby setting said        second biteplate part in a fixed first biteplate spatial        relationship with respect to said body reference and in a fixed        second biteplate spatial relationship with respect to said first        biteplate part via said coupling to define said second spatial        relationship.

The second biteplate part may be aligned with said body reference. Step(a) may comprise manipulating said first biteplate part with respect tosaid second biteplate part via said coupling until said first biteplatepart is abutted to at least one tooth arch of the patient comprisingsaid part of said dental structure, while concurrently setting saidsecond biteplate part at fixed said first biteplate spatial relationshipwith respect to said body reference.

Step (a) may comprise generating a virtual model of a first zone of saidbiteplate apparatus comprising at least a portion of said couplingsufficient to indicate the relative position and orientation of saidfirst biteplate part with respect to said second biteplate part, andproviding a spatial relationship between said body reference and saidcoupling, and determining said second biteplate spatial relationshipfrom said first zone virtual model and said spatial relationship betweensaid body reference and said coupling. The said first zone virtual modelmay be generated by scanning said first zone with said scanner or withanother suitable scanner.

Step (a) may comprise generating at least a first partial virtual modelof a first zone of said biteplate apparatus comprising said part of saiddental structure and a portion of said first biteplate part coupledthereto, and generating a second partial virtual model of a second zoneof said biteplate apparatus including at least a portion of saidcoupling sufficient to indicate the relative position and orientation ofsaid first biteplate part with respect to said second biteplate part,and determining said second biteplate spatial relationship from saidfirst and second partial virtual models. The said first partial virtualmodel and said second partial virtual model may be generated byrespectively scanning said first zone and said second zone with saidscanner or with another suitable scanner.

Optionally, at least said first virtual model further comprises colourdata representative of said part of said dental structure.

The said body reference excludes a dental structure or the intra-oralcavity.

According to a variation of the first aspect of the invention there isprovided a method for providing a spatial relationship of a dentalstructure of a patient with respect to a body reference of the patient,comprising

-   -   coupling a geometrical structure to said dental structure in a        known or determinable geometrical relationship with respect to        said body reference, said geometrical structure having known or        determinable geometrical properties;    -   scanning at least a part of said dental structure coupled with        said geometric structure to generate a composite virtual model        thereof;    -   determining said spatial relationship from said virtual model,        said geometrical properties and said geometrical relationship.

According to another variation of the first aspect of the inventionthere is provided a method for providing patient data useful for dentalprocedures, comprising

-   -   scanning a dental structure of a patient when coupled to a        geometric structure to provide a virtual model representative of        said coupling and said dental structure, and relating said        virtual model to a body reference of the patient.

Said body reference excludes a dental structure.

According to another variation of the first aspect of the inventionthere is provided a method for providing a spatial relationship of adental structure of a patient with respect to a body reference of thepatient, comprising

-   -   generating a first virtual model representative of at least a        part of said dental structure coupled with a geometric structure        in a first spatial relationship therewith, wherein a second        spatial relationship between said geometric structure and said        body reference is known or determinable, wherein said first        virtual model is generated by scanning said part of said dental        structure coupled with said geometric structure with a suitable        seamier;    -   determining the spatial relationship between said part of said        dental structure and said body reference from said first spatial        relationship and said second spatial relationship.

Said body reference excludes a dental structure.

The method according to at least one of the above variations of firstaspect of the invention, may optionally further comprise one or more ofthe features listed above for the method according to the first aspectof the invention, mutatis mutandis, in any suitable combination.

According to the first aspect of the invention, the determined spatialrelationship between said part of said dental structure and said bodyreference may be used in a suitable dental procedure, for example aprosthodontic procedure, an orthodontic procedure, a dental articulationprocedure, and so on.

According to the first aspect of the invention, the aforementionedmethods may be implemented by means of a suitable computer.

According to a second aspect of the invention there is provided a methodfor providing a spatial relationship of at least a part of dentalstructure of a patient with respect to a body reference of the patientcomprising generating a first virtual model representative of said atleast a part of said dental structure coupled with said body reference,and determining said relationship from said first virtual model.

For example, said body reference comprises an external mouth structureof the patient, for example at least one of the lips of the patient in apredetermined state. For example, said predetermined state constitutessmiling by the patient, wherein said at least one lip defines a smileline of the patient. In at least some embodiments, said dental structureincludes at least one dental preparation that is visually coupled tosaid body reference, and the method may further comprise generating aprosthesis virtual model representative of a prosthesis configured formounting to a respective said preparation, wherein a cusp line of saidprosthesis virtual model is aligned to match said smile line.

Alternatively, the body reference may comprise the TMJ or ear canals ofthe patient, and the first virtual model comprises this body referenceas well as a zone of the head of the patient including the bodyreference and extending therefrom to the said part of dental structureof a patient in a contiguous manner.

The method according to the second aspect of the invention may furthercomprise providing a virtual model of a second dental structure thatincludes said part of said first-mentioned dental structure, anddetermining the spatial relationship between said second dentalstructure and said body reference from said first spatial relationship,said second spatial relationship, and registering said virtual model ofsaid second dental structure with said first virtual model. Said virtualmodel is generated by scanning said part of said dental structurecoupled with said body reference with a suitable scanner. For example,said scanner may be an optical scanner, and optionally operation of saidscanner may be based on confocal imaging techniques. Such a scanner maycomprise, for example:

-   -   a probing member with a sensing face;    -   first illumination means for providing a first array of incident        light beams transmitted towards the structure along an optical        path through said probing unit to generate illuminated spots on        said portion along said depth direction, wherein said first        array is defined within said reference array;    -   a light focusing optics defining one or more focal planes        forward said probing face at a position changeable by said        optics, each light beam having its focus on one of said one or        more focal plane;    -   a translation mechanism for displacing said focal plane relative        to the structure along an axis defined by the propagation of the        incident light beams;    -   a first detector having an array of sensing elements for        measuring intensity of each of a plurality of light beams        returning from said spots propagating through an optical path        opposite to that of the incident light beams;    -   a processor coupled to said detector for determining for each        light beam a spot-specific position, being the position of the        respective focal plane of said one or more focal planes yielding        maximum measured intensity of the returned light beam, and based        on the determined spot-specific positions, generating data        representative of the topology of said portion.

Optionally, at least said virtual model further comprises colour datarepresentative of said part of said dental structure coupled with saidbody reference.

Said body reference may be, for example, at least one of an imaginarypoint, line or zone on the patient's face, the method further comprisingmarking said respective point, line or zone with a material that hasoptical contrast with the neighbouring portions of the face thereto. Forexample, said body reference comprises a said line aligned with themidsagittal plane of the patient.

Said body reference excludes a dental structure.

According to a third aspect of the invention, there is provided anapparatus for use in providing a spatial relationship of a dentalstructure of a patient with respect to a body reference of the patient,comprising a geometrical structure comprising a first part alignablewith said body reference, and a second part that in use is coupled withsaid dental structure, wherein said body reference excludes the earcanals or TMJ of the patient.

For example, said body reference is a sagittal plane of the patient.

Said second part may comprise a bite plate configured for being abuttedwith respect to a dental arch comprising said dental structure, and saidfirst part comprises an arm pivotably mounted to said bite plate suchthat in operation of said apparatus, said bite plate may be received inthe intra-oral cavity of the patient abutted to said dental arch, whilesaid arm remains outside the intra oral cavity.

The apparatus may be configured for enabling said arm to be aligned witha midsagittal plane of the patient when said bite plate is abutted withrespect to the dental arch. The first part may comprise a first stripalignable with said body reference, and wherein said second partcomprises a second strip that in use of the apparatus is superposed overthe open mouth of the patient such as to optically couple the secondstrip with said dental structure, and wherein said first strip and saidsecond strip are joined to one another in a known or determinable mannervia an interconnecting portion. For example, said interconnectingportion may comprise a piece of sheet material having an opening sizedto enable the nose of the patient to protrude therefrom when theapparatus is in use.

Alternatively, said first part comprises a frame that is configured tobe centered over the eyes of the patient when in use, and wherein saidsecond part comprises a second strip that in use of the apparatus issuperposed over the open mouth of the patient such as to opticallycouple the second strip with said dental surfaces, and wherein saidframe and said second strip are joined to one another in a known ordeterminable manner via an interconnecting portion. For example, saidframe may comprise a piece of sheet material having an opening sized toenable the nose of the patient to protrude therefrom when the apparatusis in use. Optionally, the apparatus may further comprise side elementsfor resting said apparatus on the ears of the patient, and a bridgeportion for resting on the nose of the patient.

According to a variation of the third aspect of the invention there isprovided an apparatus for use in providing a spatial relationship of adental structure of a patient with respect to a body reference of thepatient, comprising a geometrical structure comprising a first partcoupled to a second part, said first part being alignable with said bodyreference, and said second part being configured for being coupled tosaid dental structure in operation of said apparatus, said second partbeing further configured to provide a portion that is optically exposedwith respect to said dental structure when coupled thereto, saidoptically exposed portion being configured for enabling a position andorientation of the second part with respect to the dental structure tobe determined based on a virtual model that may be generated by suitablyscanning said second part when coupled to said dental structure.

Said second part may comprise a biteplate, and said exposed portion maycomprise indicia that facilitate said determination of said position andorientation of the second part with respect to the dental structure. Thevisually exposed part may comprise at least one projection outwardlyextending from a periphery of said bite plate.

For example, said apparatus may be configured to provide at least onedegree of freedom between said first part and said second part.

Said first part may comprise a bracket in the form of a U having a pairof arm portions spaced by a base portion, the arm portions comprisemeans for engaging the ear canals of the patient at a reference axis ofthe first part, and said bite plate is connected to the base portion viaa coupling configured for providing at least two degrees of freedombetween the bite plate and the base portion.

Said coupling may be configured for enabling translation and a rotationof said bite plate with respect to said base portion. Alternatively,said coupling may be configured for enabling a first rotation and asecond rotation of said bite plate with respect to said second facebowpart, wherein said first rotation is independent of said secondrotation; said first rotation and said second rotation may compriserespective rotational axes that are mutually orthogonal.

The first part may further comprise visual indicators that facilitatedetermination of a plane including said reference axis and passingthrough one of said first axis and second axis.

Optionally, said geometrical structure further comprises indicatorswhich are adjustable to indicate a position of a body part or bodyreference axis or a body reference plane with respect to the first partor the second part when the apparatus is in use.

According to a fourth aspect of the invention, there is provided asystem for providing a spatial relationship of a dental structure of apatient with respect to a body reference of the patient, comprising:

-   -   at least one suitable scanner;    -   a computer system configured for operating according to the        method according to the first or second aspect of the invention        or variations thereof;    -   apparatus for use in providing said spatial relationship        according to the apparatus according to the third aspect of the        invention or variations thereof.

According to a fifth aspect of the invention, there is provided anadaptor for use with a dental articulator having a pair of articulatorarms hinged at an articulator axis, the adaptor comprising a baseportion a spacer element and a model mounting arrangement, wherein thebase portion is configured for mounting to an a respective said arm ofthe articulator, wherein the model mounting arrangement is configuredfor enabling a respective dental model of part or of the full respectivedental arch to be mounted thereonto according to mounting featuresprovided in the respective model, and wherein said spacer portionsrigidly interconnect the base part to the model mounting arrangementsuch as to provide a known spatial relationship between the articulatoraxis and the model when mounted to the model mounting arrangement.

According to the fifth aspect of the invention, there is also provided adental articulator comprising at least one said adaptor.

According to a sixth aspect of the invention, there is provided amachining blank for producing a physical dental model corresponding tothe jaw or maxilla of the patient, comprising a blank body configuredfor enabling a respective a dental arch model to be machined producedtherefrom via a material removal operation, and, the blank comprising anintegral arm portion having an identifiable hinge position, wherein saidblank body is configured for enabling the produced dental arch model tobe spatially located with respect to the hinge position in a mannercorresponding to the spatial location of the respective dental arch withrespect to the hinge axis of a patient's jaw hinge.

According to the sixth aspect of the invention, there is also provided aphysical dental model corresponding to the jaw or maxilla of thepatient, comprising a respective dental arch model and an integral armportion having an identifiable hinge position, wherein said dental archmodel is spatially located with respect to the hinge position in amanner corresponding to the spatial location of the respective dentalarch with respect to the hinge axis of a patient's jaw hinge.

For example, the physical dental model may be integrally produced from asuitable blank via a material removal operation or may be integrallyproduced via a suitable rapid prototyping operation.

According to another aspect of the invention there is provided a methodfor providing a spatial relationship of an in vivo dental surface of apatient with respect to a reference plane or axis of the patient,comprising generating a virtual model of at least a part of said dentalsurface coupled with a structure in a fixed spatial relationshiptherewith, wherein the spatial relationship between said structure andsaid reference plane or said reference axis is known or determinable. Inparticular, said part of said dental surface is optically coupled withsaid structure.

According to another aspect of the invention there is provided a methodfor providing data for facilitating dental procedures, comprising:

-   -   providing a first virtual model representative of at least a        portion of the intra-oral cavity of a patient;    -   providing a second virtual model, representative of at least one        structure coupled to the portion of the intra-oral cavity, said        structure defining at least one spatial parameter of interest        associated with a dental procedure;    -   determining a spatial disposition of the first virtual model        with respect to the second virtual model; and    -   generating, from this spatial disposition, data representative        of a spatial relationship between said first virtual model and        said at least one spatial parameter of interest.

The method may further comprise applying said generated data to a dentalprocedure.

According to another aspect of the invention there is provided a systemfor providing data for facilitating dental procedures, comprising ascanner, a computer system configured for carrying out the methodaccording to at least the aforementioned aspects of the invention.

According to another aspect of the invention there is provided a dentalarticulator as disclosed herein.

According to another aspect of the invention there is provided anapparatus for use in providing a spatial relationship of an in vivodental surface of a patient with respect to a reference plane or axis ofthe patient, comprising a structure comprising a first part alignablewith said reference plane or axis, and a second part that in use isoptically coupled with said dental surface. The reference plane or axismay comprise any one of a sagittal plane or midsagittal plane of thepatient, for example.

According to one embodiment, the apparatus is a bite plate apparatus foruse in providing a spatial relationship of an in vivo dental surface ofa patient with respect to said reference plane or axis of the patient,comprising a bite plate portion hingedly mounted to a vertical plateportion about a hinge, wherein the vertical plate portion is pivotableabout said hinge to be aligned with a sagittal plane of a patient, whenthe bite plate portion is in contact with at least some cusp tips of theupper arch of the patient.

According to another embodiment, the first portion comprises a firststrip alignable with said reference plane or axis, and wherein saidsecond portion comprises a second strip that in use of the apparatus issuperposed over the open mouth of the patient such as to opticallycouple the second strip with said dental surfaces, and wherein saidfirst strip and said second strip are joined to one another in a knownor determinable manner via an interconnecting portion. Theinterconnecting portion may comprise a piece of sheet material having anopening sized to enable the nose of the patient to protrude therefromwhen the apparatus is in use.

According to another embodiment, the first portion comprises a framethat is configured to be centered over the eyes of the patient when inuse, and wherein said second portion comprises a second strip that inuse of the apparatus is superposed over the open mouth of the patientsuch as to optically couple the second strip with said dental surfaces,and wherein said frame and said second strip are joined to one anotherin a known or determinable manner via an interconnecting portion. Theframe may comprise a piece of sheet material having an opening sized toenable the nose of the patient to protrude therefrom when the apparatusis in use. The apparatus may further comprise side elements for restingsaid apparatus on the ears of the patient, and a bridge portion forresting on the nose of the patient.

According to another aspect of the invention there is provided anadaptor for use with a dental articulators, comprising a base portion aspacer element and a model mounting arrangement, wherein the baseportion is configured for mounting to an arm of the articulator, whereinthe model mounting arrangement is configured for enabling a respectivedental model of part or of the full respective dental arch (upper orlower) to be mounted thereonto according to mounting features providedin the respective model, and wherein said spacer portions rigidlyinterconnect the base part to the model mounting arrangement such as toprovide a known spatial relationship between the articulator axis andthe model when mounted to the model mounting arrangement.

According to another aspect of the invention there is provided amachining blank, made from a suitable machinable material, for enablinga dental model to be machined therefrom, the blank comprising anintegral aim portion having an identifiable hinge position correspondingto the hinge axis of a patient's jaw hinge.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

In order to understand the invention and to see how it may be carriedout in practice, embodiments will now be described, by way ofnon-limiting example only, with reference to the accompanying drawings,in which:

FIG. 1 is a schematic illustration of a system according to anembodiment of the invention.

FIG. 2 illustrates in top view a facebow apparatus according toembodiments of the invention.

FIG. 3 illustrates in front view the embodiments of FIG. 2.

FIG. 4 illustrates in side view the embodiments of FIG. 2.

FIGS. 5, 5(a) 5(b) are schematic illustrations of a method according toembodiments of the invention.

FIG. 6 illustrates in side view a dental articulator apparatus accordingto an embodiment of the invention.

FIG. 7 illustrates examples of dental models designed and manufacturedfor use with the embodiment of FIG. 6 or FIG. 10.

FIGS. 8(a) and 8(b) illustrate example scans provided according to anaspect of the invention.

FIG. 9 illustrates in side view blanks for producing tooth models withintegral articulator arms.

FIG. 10 illustrates in side view a dental articulator apparatusaccording to another embodiment of the invention.

FIG. 11 illustrates a geometrical structure according to an embodimentof the invention in situ on a patient's face.

FIG. 12 illustrates the embodiment of FIG. 11 in greater detail.

FIG. 13 illustrates a geometrical structure according to anotherembodiment of the invention in situ on a patient's face.

FIG. 14 illustrates the embodiment of FIG. 13 in greater detail.

FIG. 15 illustrates in isometric view a facebow apparatus according toanother embodiment of the invention.

FIG. 16 illustrates embodiment of FIG. 15, engaged with respect to apatient.

FIG. 17 illustrates a bite fork portion of the embodiment of FIG. 15.

FIG. 18 illustrates a virtual model of a dental structure coupled withbite fork portion of the embodiment of FIG. 15.

FIG. 19 illustrates in isometric view a facebow apparatus according toanother embodiment of the invention.

FIG. 20 illustrates a bite fork portion of a variation of the embodimentof FIG. 19.

DETAILED DESCRIPTION OF EMBODIMENTS

According to a first aspect of the present invention there is provided asystem and method for use in dental procedures.

FIG. 5 illustrates a block diagram of a process 400 for providing dataaccording to an embodiment of the invention, and FIG. 1 illustrates themain elements of a system 200 for carrying out the method according toan embodiment of the invention.

The system 200 typically comprises a scanner 250, a geometric structurein the form of a facebow apparatus 100, and a microprocessor or anyother suitable computer system 260.

The computer system 260 comprises an input interface or module 210 suchas a keyboard, mouse, tablet, and so on, an output device or displaymeans or module 220, typically a screen or monitor but may additionallyor alternatively include a printer, or any other display system, acomputer processing unit or module 230 such as for example a CPU, and amemory 240.

The scanner 250 is configured for providing surface data of structures,in particular dental surfaces of dental structures, of other tissuesurfaces of the face and head of a patient, and of the facebow apparatusor other geometric structures, and is also operatively connected to thecomputer system 260 and interacts therewith. The computing system 260 issuitably programmed for reconstructing such surfaces from the surfacedata provided, to provide a corresponding virtual model of the structurescanned by the scanner. Such a scanner may comprise, for example, anysuitable non-contact scanner, for example an optical scanner. By way ofnon-limiting example, the scanner 250 may include a probe fordetermining three dimensional structure by confocal focusing of an arrayof light beams, for example as marketed under the name of iTero byCadent Ltd., or as disclosed in WO 00/08415, the contents of which areincorporated herein in their entirety. Alternatively, the requiredscanning may be accomplished using any other suitable scanningapparatus, for example comprising a hand held probe.

Optionally, color data of the intraoral cavity may also providedtogether with the 3D data, to provide corresponding virtual model thatcomprise spatial (3D) as well as color information of the structuresscanned, such as for example of dental surfaces. Examples of suchscanners are disclosed in US 2006-0001739, and which is assigned to thepresent Assignee. The contents of the aforesaid co-pending applicationare incorporated herein by reference in their entirety.

The facebow apparatus is configured for providing sufficient spatialinformation for defining the position of the dental arches of a patientin three-dimensions with respect to the hinge axis of the patient's jaw.Referring to FIGS. 2 to 4, a facebow apparatus according to a firstembodiment of the invention, which is per se novel, is generallydesignated with reference numeral 100, and comprises a facebow portion120 and a bite fork portion 140.

The facebow portion 120 is in the form of a U-shaped member adjustablein two, generally orthogonal directions, enabling this component to befitted to a range of patients having widely differing anatomies.

The facebow portion 120 comprises a pair of L-shaped arms 123, eachcomprising a first member 124 joined to a second member 126 at an anglethereto, typically orthogonal, though in alternative embodiments may beacute or obtuse, the first member 124 being telescopically movable withrespect to a common central member 122 in a controllable manner enablingthe two first members 124 to be reversibly fixed at any desired relativedisposition with respect to the central member 122, along directionsindicated by the arrows 162. In alternative variations of thisembodiment, the two first members 124 may be mechanically coupled, forexample via a rack and pinion arrangement (not shown), comprising apinion gear rotatably mounted inside said central member 122, and thetwo first members 124 each comprising a rack that is meshed atdiametrically opposed sides of the pinion gear, enabling simultaneousand synchronized extension/retraction movements of the two first members124 with respect to the central member 122.

Each of the respective second members 126 extends in a general rearwardsmanner from central member 122, and is telescopically adjustable,comprising an inner member 126 a controllably reciprocable with respectto outer member 126 b to allow length adjustment in the directionsmarked 164, and reversibly fixable with respect thereto. At or close toa free end of each of the inner members 126 a there is an ear canalinsertion portion 129 for engagement to the ear canals of a patient.

A scale 127 is marked or printed on the inner member 126 a, enabling therelative dispositions between the inner member 126 a and outer member126 b of each of the arms 126 to be determined. For example, the scale127 may be marked to give the displacement of the center 129 a of theear canal insertion portions 129 from the rear portion 121 of thecentral member 122 in an orthogonal direction therefrom generally alongthe second member 126. In alternative variations of this embodiments,landmarks, symbols or surface features may be provided on the innermember 126 a which are individually visually recognizable and thelocation of which with respect to the corresponding inner member 126 aand in particular portion 129, is known.

Each second members 126, in particular the respective inner member 126a, further comprises a pointer 132 controllably slidable along thelength thereof, and for reversibly locking at any desired locationthereon; for example, the pointer may be magnetically or mechanicallyfixable to the corresponding inner member 126 a. Each pointer 132 pointsin an inward direction, generally parallel to said ear canal insertionportions 129, and is configured for being brought into registry with thehinge axis or TMJ of the patient's jaw when the portions 129 are engagedwith the patient's ears.

The central member 122 comprises a nose interface 130 on rear portion121, having a concavity configured for abutting against a part of thenose of the patient, for example the bridge. The front portion 128 ofthe central member 122 comprises a slot 125 defined by a bar 135 spacedfrom the frontal portion 128 and extending along part or most of thelength thereof.

A representative plane P for the facebow portion 120 may be defined bythe three points including the centers 129 a of the two portions 129 anda particular point 131 on the nose portion 150.

The bite fork portion 140 comprises a bite plate 142 having a lowersurface 142 b, and further having an upper surface 142 a which in useabuts against the cusp tips of the maxillary arch, or at a least aportion thereof, and a vertical plate 144 that is hingedly mounted tothe bite plate 142 at hinge 143 to allow the orientation therebetween tobe varied about hinge axis 145. Vertical plate 144 is in use generallyaligned with the midsagittal plane of the patient, or alternatively withanother sagittal plane of the patient, and hinge axis 145 issubstantially aligned with the vertical plate 144 such as to enable thebite plate 142 to be angled at angle a to the vertical plate 144.

A connecting bar 150 coplanarly aligned with the vertical plate 144extends therefrom in a direction generally away from the bite plate 142,and in use is received in said slot 125. The spacing between the rod 135and the front face 128 of slot 125 is sufficiently wide to enable theconnecting bar 150 to extend an angle p with the frontal plane of thepatient. Optionally (not shown) a suitable securing arrangement may beprovided for reversibly securing the connecting bar 150 with respect tothe slot 125 in a particular spatial relationship.

Referring again to FIG. 5, process 400 broadly includes the followingsteps:

Step 410—providing a first virtual model 500 representative of at leasta portion of the intra-oral cavity of a patient, such as a dentalstructure, for example.

Step 430—providing a second virtual model 600, representative of atleast one geometric structure coupled to the portion of the intra-oralcavity, in particular at least a part of the dental structure, saidgeometric structure defining at least one spatial parameter of interestassociated with a dental procedure, or alternatively, said at least onespatial parameter of interest may be determined by means of thegeometric structure.

Step 450—determining a spatial disposition of the first virtual modelwith respect to the second virtual model.

Step 470—generating, from this spatial disposition, data representativeof a spatial relationship between said first virtual model and said atleast one spatial parameter of interest.

The data generated in step 470 can then be used in a desired dentalprocedure 480 for which it may be useful.

In the first embodiment of the invention, data is provided relating tothe spatial relationship between a maxillary arch, or a part thereof,and the hinge axis H of the jaw of a patient, which data may then usedfor constructing physical models of the tooth arches that engage with adental articulator in a spatial relationship with the articulator hingeaxis that parallels the corresponding relationship in the patient.

Step 410 comprises acquiring an accurate 3D representation, (herein alsoreferred to interchangeably as “three-dimensional model”, “3D model”,“virtual model” and the like) of the required part of the intraoralcavity of the patient, for example dental structures, which forms thefocus of a particular dental procedure for a particular patient andregarding which it is desired to obtain the 3D topographical or surfacedata thereof. The required part may include may include dentalstructures such as one or more teeth, or partial or the full mandibularor maxillary arches, or both arches, and/or include details of thespatial relationship between the two arches in occlusion.

In any case, this first virtual model may be provided by scanning theintra-oral cavity in-vivo using any suitable equipment for scanning apatient's teeth. Such scanning equipment may include any suitableoptical scanner, for example, the scanner 250 of system 200, or asimilar scanner that is not part of the system 200, or a different typeof scanner. Alternatively, the first virtual model 500 may be obtainedfrom a physical model of the teeth of the particular patient that waspreviously prepared. For example, the surfaces of the physical model maybe scanned, or the surfaces of the impression from which the model wasscanned may be scanned to obtain the virtual model thereofAlternatively, a composite positive-negative model may be manufacturedand processed to obtain 3D digitized data, for example as disclosed inU.S. Pat. No. 6,099,314, assigned to the present Assignee, and thecontents of which are incorporated herein in their entirety.Alternatively, the 3D digitized data may be obtained in any othersuitable manner, including other suitable intra oral scanningtechniques, based on optical methods, direct contact methods or anyother means, applied directly to the patient's dentition or to aphysical model thereof Alternatively, X-ray based, CT based, MRI based,or any other type of scanning of the patient or of a positive and/ornegative physical model of the intra-oral cavity may be used.

In step 430, the second virtual model 600 is obtained, using system 200,as follows.

Referring to FIG. 5(a), in step 431, the bite fork portion 140 isengaged with at least the upper dental arch of the patient—in practice,the patient can clamp the surfaces 142 a and 142 b of the bite plate 142between the upper and lower dental arches. The practitioner then rotatesthe vertical plate 144 and rod 150 about axis 145, so that they arealigned with the midsagittal plane, or at least such that the verticalplate 140 is co-planar with therewith, but possibly spaced therefrom,while the upper surface 142 a is abutted against the cusp tips of theupper teeth. This defines an angle a between the plane defining the cusptips of the upper arch and the vertical plane.

In step 433, the facebow portion 120 is mounted onto the patient byengaging the ear canal insertion portions 129 in the respective earcanals of the patient, and resting the nose interface 130 on a positionon the patient's nose such as to ensure that the pointers 132 arealigned with the position of the jaw hinge axis H. This position ispreviously marked on the skin of the patient by the practitioner in amanner, as is well known in the art. If necessary, the lateral spacingsbetween the arms 123 along direction 162, and/or the spacing between theportions 129 and the central portion 122 along direction 164, may beadjusted as necessary to account for the particular anatomy of thepatient and to orient the facebow portion 120 in the required manner,i.e., constrained by the location of the ear canals and of the hingeaxis of the patient, and the plane P of the facebow portion 120 istypically inclined at an angle 0 to the horizontal plane H.

The rod 150 is received within the slot 125 and fixed in place withrespect thereto, the rod still being maintained aligned with themidsagittal plane or at least a sagittal plane.

The various components of the facebow apparatus 100 are secured withrespect to one another in the positions provided in the earlier steps sothat the facebow apparatus may be considered as a rigid body, at leastwhile step 434 is in progress. Further, the facebow apparatus 100 ismechanically coupled with the intra-oral cavity and with respect to thehinge axis H of the jaw.

In step 434, the scanner 250 is used to scan a number of portions of thefacebow apparatus 100 in situ with respect to the part of the dentition,i.e., the dental structure, it is coupled with, as follows, referring toFIG. 5(b) and FIGS. 2 to 4.

Step 434 a—a first zone Z1 is scanned including at least a part of thebite plate 142, vertical plate 144 and at least a portion of themaxillary teeth that are in contact with surface 142 a. The first zoneZ1 scan is at least sufficient to ensure that enough of the bite forkportion 140 may be reconstructed in a portion 602 of the second virtualmodel from the scan, so that a virtual vertical plane corresponding tothe vertical plate 144, and a virtual cusp tip surface corresponding tothe upper surface 142 a can be defined to a preset accuracy. At leastsome of the dental surfaces in contact with the bite plate, inparticular dental surfaces comprised in the maxillary arch are alsoscanned together with the bite fork, so that the second virtual modelincludes a virtual portion corresponding to these dental surfaces incontact with the bite plate.

Step 434 b—a second zone Z2 is scanned including at least a part of therod 150 and its intersection with the slot 125. The second zone Z2 scanis at least sufficient to ensure that enough of the rod 150 and centralmember 122 may be reconstructed in a portion 604 of the second virtualmodel, so that the position and orientation of a virtual entitycorresponding to the rod 150 with respect to the central member 122 canbe defined to a preset accuracy. The position of rod 150 with respect tothe central member 122, in particular the rod 135, and angle β along thesagittal plane with respect to which the rod 150 is nominally aligned,between the rod 150 and the vertical plane V in turn enables thelocation in 3D of the bite fork apparatus 140 to be defined with respectto the central member 122, and thus to the facebow portion 120.

Step 434 c—a third zone Z3 is scanned including a part of at least one,and preferably each of the arms 123, including in each case a part ofthe respective inner member 126 a that is in visibly adjacent therespective outer member 126 b. The scan is at least sufficient to ensurethat enough of the inner member 123 a and the respective outer member123 b may be reconstructed in a portion 606 of the second virtual model,so that the relative disposition therebetween of a virtual entitycorresponding to the respective arm 123 can be defined to a presetaccuracy. This enables the relative location of the respective portion129 to the central member 122 in the virtual model to be determined, andin turn enables the location in 3D of the bite fork portion 140 to bedefined with respect to the ear canal engagement portions 129. Inalternative variations of this embodiment, in which the facebow portion120 is non-adjustable, step 434 c may be omitted. In yet otheralternative variations of the invention, it may be possible to simplyread off the scale 127, and input this data to enable the relativelocation of the respective portion 129 to the central member 122 to bedetermined.

Step 434 d—a fourth zone Z4 is scanned including a part of at least one,and preferably each of the arms 123, including in each case at least apart of the respective pointer 132 and a part of the respective innermember 126 a that is in visibly adjacent the pointer 132. The fourthzone Z4 scan is at least sufficient to ensure that enough of the innermember 123 a and the respective pointer 132 may be reconstructed in aportion 608 of the second virtual model, so that the relativedisposition therebetween of a virtual entity corresponding to thepointer and its position on the respective arm 123 can be defined to apreset accuracy. This enables the relative location of the pointer 132with respect to the facebow portion 120 in the virtual model to bedetermined, and in turn enables the location in 3D of the bite forkapparatus 140 to be defined with respect to the jaw hinge axis. Inalternative variations of this embodiment, step 434 d may be omitted.

In steps 434 c and 434 d, the scale 127 may provide useful clues fordetermining the relative positions of the portion 129 and of the pointer132 with respect to the facebow portion 120 in the virtual model.

Optionally, steps 434 c and 434 d may be combined so that a zone Z5 isscanned including the pointer 132 and, contiguously therewith, theintersection 133 between the inner member 126 a and 126 b as viewed fromoutside the apparatus 100. This enables the position of the pointer 132relative to the intersection 133, and thus with respect to the bite forkportion 140 and so on to be determined, and thus enable portions 606 and608 of the second virtual model 600 to be reconstructed together.

The preset accuracy required in each step may depend on the specificdental procedure regarding which the generated data is to be appliedlater.

The virtual model 600 may be completed by combining the portions 602,604, 606 and 608 in their relative special positions. This may be donein a number of ways. For example, a third virtual model of the facebowapparatus 100 may be provided within the computer environment of thecomputer system 260, the third virtual model being manipulable to enablethe relative dispositions and movements of the movable components in thereal facebow apparatus 100 to be simulated. Thus, the third virtualmodel is effectively a combination of “component” virtual models, eachcorresponding to a respective one of the various components of thephysical facebow apparatus 100. Each of the portions 602, 604, 606 and608 is registered or otherwise matched with respect to the correspondingpart of the third virtual model, by manipulating the component virtualmodels thereof, such that each aforesaid portion is in registry with thecorresponding part of the third virtual model. The third virtual modelis thus effectively manipulated in a manner to simulate the relativedispositions of the components in the physical model of the facebowapparatus, and the second virtual model 600 is then generated byeffectively adding the dental surface reconstructed on the bite plate,as provided in step 434 a.

Alternatively, it is sufficient to spatially combine the portions 602,604, 606 and 608 within the computer environment in their respectivecorrect relative positions, and this provides the second virtual model600. To do so, each portion is manipulated so as to conform to a common,global coordinate system, and this may be done by identifying particularlandmarks or features in each portion, determining the correspondingposition of such landmarks in a nominal virtual model of the facebowapparatus, and applying a corresponding transformation to the particularportion to conform to the same coordinate system as in the aforesaidnominal virtual model. Such features may correspond to features in thephysical facebow including, for example, the intersection 133, the frontface 128, the attachment point between the bar 150 and the verticalplate 144, and so on.

Thus, in step 430, the structure in the form of the facebow apparatus100 is mechanically coupled to the dental structure. In alternativevariations of this embodiment it may only be necessary to spatiallycouple any suitable geometrical structure to the dental structure in afixed spatial relation that is determinable from a virtual model of thecoupled structures via scanning thereof, the geometrical structure beingsuch that its spatial relationship to a body reference, for examplebasic reference planes or axes of the head of the patient, is alsoconcurrently known or determinable, enabling the spatial relation of thedental structures to the aforesaid body reference such as basicreference planes or axes to be determined from the scanning. Thus,according to an aspect of the invention there is provided a method forproviding a spatial relationship of the dental structure of a patientwith respect to the desired body reference of the patient, comprising:

-   -   (A) generating a virtual model representative of at least a part        of said dental structure coupled with the geometric structure in        a first spatial relationship therewith, wherein a second spatial        relationship between said geometric structure and said body        reference is known or determinable; and    -   (B) determining the spatial relationship between said part of        said dental structure and said body reference from said first        spatial relationship and said second spatial relationship.

Thus, step (A) is analogous to step 430, including steps 431 and 433,for example, and step (B) is analogous to step 434, modified asnecessary according to the specific type of geometrical structure thatis coupled to the dental structure, mutatis mutandis.

In step 450 the spatial disposition of the first virtual model withrespect to the second virtual model is determined by registering thevirtual model of the dental surfaces obtained in step 434 a with thefirst virtual model. Such registration is conducted in the computerenvironment of computer system 260 by manipulating one or another orboth of the first virtual model 500 and the second virtual model 600 sothat the virtual dental model surfaces in the second virtual model,obtained via step 434 a, coincide with a corresponding part of the firstvirtual model. As the dental surfaces are rigid structures, and assumingthat there have been no changes in the dentition between steps 410 and430, the virtual dental surfaces in both virtual models should bematchable to a high degree of accuracy. Once matched, the spatialrelationship of the bite plate 142, and thus of the vertical plate 144and the sagittal plane thereof, the spatial relationship of the hingeaxis as determined by pointers 132, and so on, with respect to the firstvirtual model 500 are automatically determined.

In alternative variations of this embodiment, step 410 may be omitted.For example, in step 430 the dental structure may be sufficientlydefined by the scanning of the coupled dental structure/geometricstructure for the purposes of the user. Thus step 450 may also beomitted. To separate the surface data corresponding to the dentalstructure from the surface data corresponding to the geometricalstructure that is scanned in situ with the dental structure, if this isdesired, may be accomplished by registering a virtual model of the partof the geometrical structure that is coupled to the dental structurewith a virtual model of this geometrical structure (obtainedindependently of the scan at step 430), or by identifying anddistinguishing surface data corresponding to the dental structure fromthe surface data corresponding to the geometrical structure.

In step 470, any suitable desired data relating to spatial dispositionof the first virtual model to the second virtual model can be generated,this data being representative of a spatial relationship between thefirst virtual model and said at least one spatial parameter of interest.In one particular application of the embodiment, the parameter ofinterest is the hinge axis H of the jaw of the patient, and theaforesaid data relates to the disposition of the first virtual model 500relative to the virtual representation of the hinge axis, HA.

The data generated in step 470 can then be used in a desired dentalprocedure 480 for which it may be useful. Such a procedure 480 may bethe construction of a physical articulation model of the teeth of thepatient, and the relative disposition of the first virtual model 500 tothe virtual hinge axis HA may be used to enable a physical model of theteeth to be mounted onto a particular articulator such that they arepositioned therein in six degrees of freedom in a spatial relationshipwith the articulator hinge axis in a manner simulating that generated instep 470 for the virtual model.

For example, the first virtual model may be further manipulated toinclude an alignment arrangement, for example as disclosed in U.S. Pat.No. 7,220,124 to the present Assignee, and the contents of which areincorporated herein in their entirety.

A physical model may be manufactured from the first virtual model—forexample via a material removing process such as CNC or via any othersuitable process, for example rapid prototyping, the physical modelcomprising a physical representation of the alignment arrangement, whichenables the physical model of the teeth to be mounted directly to therespective dental articulator in the correct spatial orientation withrespect to the articulator hinge axis, and in proper occlusionarrangement.

Referring to FIGS. 6 and 7, an embodiment of such an articulator,designated herein with reference numeral 10, comprises an upper arm 20Aand a lower arm 20B hingedly joined together with respect to pivot axis99 at hinge arrangement 31, each arm comprising a mounting bracket 40formed therewith, comprising a model mounting arrangement 60.

The model mounting arrangement 60 is configured for enabling a dentalmodel of part or of the full respective dental arch (upper or lower) tobe mounted thereonto. In the illustrated embodiment, such mounting isreversible, but in alternative embodiments of the invention the modelmounting arrangement may permanently mount the dental models to thecorresponding arms 20A, 20B. Thus, in alternative embodiments of theinvention, the details of the mounting arrangement 60 may vary accordingto the particular geometry of the dental model, in particular theengagement arrangement thereof, if any.

The articulator 10 according to the illustrated embodiment is configuredfor use with physical dental models 100A, 100B, each of which maycomprise a positive teeth representation of one or more teeth 110,formed on a respective base 120, and further comprising a respectivemounting block 130 formed at one end of the corresponding model 100A,100B that is in closest proximity to the relative position of the axis Hof the real jaw. In this embodiment, each mounting block 130 is formedwith an abutment surface 131A, 131B, respectively, and comprises analignment arrangement comprising a pair of laterally-spaced (orotherwise spaced) cylindrical apertures 135.

In the illustrated embodiment, the mounting arrangement 60 comprises apair of transversely spaced, substantially parallel engagement prongs 70that are configured for reversibly engaging with respect to theapertures 135 of the corresponding tooth model 100, and an abutmentsurface 48 of the respective arm. The positions and orientations of theprongs 70 and abutment surfaces 48 of each arm 20A, 20B, in relation tothe hinge axis 99, are known for the particular articulator. The pair ofapertures 135 are longitudinally and laterally located on thecorresponding models 100A, 100B in a particular manner with respect tothe teeth representations 110, and furthermore the abutment surfaces131A and 131B are each inclined with respect to the occlusal plane, soas to provide the desired spatial relationship between the models 100A,100B and their occlusal plane with respect to the axis 99 when mountedto the articulator 10.

Thus, the tooth models can be designed in a virtual manner starting withthe aforesaid first virtual model, and then adding to this model, in avirtual sense (i.e., within the computer environment of computer system260 or another computer system), virtual representations of the mountingblocks 130, the particular geometry of each mounting block beingdesigned such as to displace and/or rotate the first virtual model in upto six degrees of freedom so that the cusp tip plane thereof is in thecorrect relationship to the hinge axis AH when mounted to a geometry asdefined by the arms, hinge and mounting arrangement 60 of the particulararticulator 10.

The teeth representations 110 may include representations of the teethof part or the full dental arch, and may optionally contain one or morerepresentations of one or more dental preparations in place ofcorresponding teeth, the preparations being for the purpose of fittingdental prostheses thereto.

Each prong 70 comprises a cylindrical base 72 projecting from abutmentsurface 48, and a resilient portion 74 projecting from the base 72. Theresilient portion 74 comprises a plurality of elongate resilientelements 78 cantilevered with respect to the base 72 in circumferentialarrangement and circumferentially spaced via longitudinal gaps 76. Theelements 78 each comprises a sloping portion 78 a that radially slopestowards the longitudinal axis 92 of the prong 70, and an enlargedportion 78 b at the free end of the prong 70 that radially projectsfurther outwardly than the perimeter of base 72 when the elements 78 arein the datum, unstressed condition. The enlarged portion 78 b comprisesa conical or rounded free end, a convex waist portion 78 d defining theradially outermost surfaces of enlarged portions, and an engagingshoulder adjacent the sloping portion 78 a. Thus, together the pluralityof elements 78 form a substantially frustoconical or pyramidal portioncomprising the sloping portions 78 a, and a bulging portion (comprisingthe enlarged portions 78 b) having a rounded free end.

The external width or diameter of the base 72 is just less than theinternal width or diameter of the apertures 135, and the elements 78 andgaps 76 are configured for enabling the elements 78 to be radiallyelastically deflected inwardly, such that the radially outermostsurfaces of enlarged portions 78 b, i.e. defining waist 78 d, aredisplaced from axis 92 to a distance from the centerline 92 of theelements 78 substantially equal to the radius of the apertures 135.

The longitudinal length of the prong 70 is greater than the depth ofaperture 135, and the latter is substantially similar to the sum of thelongitudinal length of the base 72 together with the longitudinal lengthof the sloping portions 78 a taken along axis 92. In other embodiments,though, the apertures 135 may be diverging or stepped, for example, orotherwise configured, for enabling the prongs 70 to be anchored withinthe corresponding apertures 135 via the restoring force generated ontothe aperture walls by the elements 78.

To engage a tooth model to the corresponding bracket 40, the respectivemounting block 130 is brought into proximity with the respective arm 20Aor 20B such that the prongs 70 are aligned with the apertures 135 of therespective model 100A or 100B. The mounting block 130 is then pushedtowards the abutment surface 48 so that the prongs 70 are received intothe apertures 135. In doing so, the corresponding elements 78 of theprongs 70 are elastically deformed, so as to enable the enlargedportions 78 b to pass through the aperture 135, this being facilitatedvia the rounded free ends 78 c. When the block 130 is in abutment withabutment surface 48, the enlarged portions 78 a fully clear theapertures 135 and spring back to the unstressed state, or closerthereto, and engage against an outer surface of the block 130 around themouth of apertures 135, locking the block 130, and thus the tooth model100A or 100B, in place.

In variations of this embodiment, more than two prongs may be provided,mutatis mutandis, the tooth models 100A, 100B being correspondinglyconfigured for being engaged thereto. In yet other variations of thisembodiment, a single prong may be provided, mutatis mutandis, and thismay optionally be further configured for preventing relative rotationbetween the corresponding tooth model and the bracket 40 about thelongitudinal axis 92 of the prong, for example comprising a suitablecircumferential stop arrangement or a non-axisymmetric cross-section.

To disengage the tooth model 100 from the mounting bracket 40, the block130 may be pulled away from the abutment surface 48. In doing so, theelements 78 must be deformed inwardly, and this may be done manually orby means of a tool, for example pliers. Alternatively, the shoulders 78e may be suitably sloped or rounded, and/or the mouth of the apertures135 may also be suitable sloped or rounded, so that as the block 130 ispulled away the elements 78 are automatically pushed inwardly in theradial direction.

To further facilitate disengagement, a quick release probe 49 may beprovided in each arm 20. The probe 49 comprises a pushing element (notshown) at the end of a shaft 49 a that is reciprocally mounted freely tothe mounting bracket 40 in a direction substantially parallel to axis92, and located generally inbetween the prongs 70. A knob 49 b isprovided at the projecting end of the shaft 49 a. The pushing element isnormally accommodated in a recess (not shown) in the abutment surface48, so as to enable the pushing element to be flush therewith when inthe inactive condition. When it is desired to disengage the tooth model100, the probe 49 is actuated by pushing the same towards the bracket40, and the pushing element forces the block 130 away from the bracket40. Once the enlarged portions 78 b have been deformed and areaccommodated in the apertures 135, the model may be fully removed fromthe bracket 40 with relative ease.

Optionally, a pivot stop 85 may be provided, configured for limiting therelative rotation of the arms 20A, 20B towards each other such toprevent the teeth models 100A and 100B being pressed against each otherwith undue force or beyond the occlusal plane. Stop 85 comprises agenerally rigid strut 86 connected to arm 20A and projecting towards thesecond arm 20B. Strut 86 essentially abuts against a surface of arm 20Bwhen the articulator is in the occlusal position, which allows the teethmodels (not shown in this figure) to touch at the occlusal plane, butprevents further rotation of the arms 20A, 20B towards one another,while permitting rotation away from one another. Optionally, the strut86 may be adjustable via a screw 88, which enables the strut to bedisplaced further towards or away from the lower arm 20B to define adifferent stop position.

The arms 20A, 20B may be made from or comprise any suitable materials orcombination of materials, for example metals (including, for example,aluminium, stainless steel, brass, titanium, and so on), plastics(including for example flexible plastics and/or hard plastics), wood,composites, ceramics, and so on.

In an alternative variation of this embodiment, the teeth models aredesigned virtually, and subsequently manufactured, for example via CNCmachining/milling methods, other material removal methods, or by rapidprototyping methods, each tooth model integrally with articulator armsand a part of a hinge arrangement, so that the two tooth models can behingedly attached to one another at the hinge arrangement. The integralarms are virtually attached to the first virtual model of the dentitionto provide the hinge axis thereof to be provided at the correct spatialrelationship to the models, as determined by the scanning of the facebowapparatus. For example, and referring to FIG. 9, such as integralarticulated physical model may be manufactured as two separatecomponents from two standard blanks, 501, 502, which are then hingedlymounted to one another at hinge axis 510. The first blank 501,representing the upper arch of the patient, is formed with anarticulation arm 503 (including integral hinge part 510 a) and integralmachinable block 505, which is then milled or otherwise machined via CNCinstructions to produce a physical model of the upper arch of thepatient (or part thereof) at the correct position and orientation withrespect to axis 510, simulating the real arch of the patient and itsrelative orientation and position with axis H of the patient. The secondblank 502, representing the lower arch of the patient, is formed with anarticulation arm 504 (including integral hinge part 510 b) and integralmachinable block 506, which is then milled or otherwise machined via CNCinstructions to produce a physical model of the lower arch of thepatient (or part thereof) at the correct position and orientation withrespect to axis 510, simulating the real arch of the patient and itsrelative orientation and position with axis H of the patient. The twomachined models 501 and 502 can then be mounted together at the hingeparts 510 a, 510 b, to mutually align the hinge axis 510. The shape andform of the arms 503, 504 may be standard, for example, at least for arange of patient attributes such as age, sex, ethnic group, and so on,while the size and position of the respective blocks, 505, 506, are suchto allow any reasonable tooth or arch geometry to be machined therefrom.

Another embodiment of an articulator arrangement according to theinvention is illustrated in FIG. 10, comprising a basic articulator 640and adaptors 620, 630. Basic articulator 640 represents an articulatoronto which a plaster model may be mounted according to the prior art,for example any suitable standard articulator currently marked undermany different well-known brand names. Alternatively, the articulator640 may comprise any other suitable dental articulator. In any case, thearticulator 640 comprises arms 641, 642 hingedly mounted together athinge axis 643, and may comprise a stop 644 mounted to arm 641 andconfigured for limiting rotational movement between the arms in adirection towards one another. Adaptors 620, 630 are mounted to theupper arm 641 and lower arm 642, respectively, of the articulator 640,and are configured for enabling tooth models 100A, 100B of the upper andlower jaws, respectively, as disclosed herein with respect to FIG. 7,for example, to be mounted to the articulator 640 in the correct spatialrelationship with respect to the hinge axis 643. Each adaptor 620, 630comprises a base part 631, a model mounting arrangement 664, and spacerportion 636.

The base part 631 is configured for mounting the adaptor 620 or 630 tothe respective arm 641 or 642 in a known and fixed spatial relationship.The model mounting arrangement 664 similar to model mounting arrangement60 disclosed for the embodiment of FIG. 6, mutatis mutandis, andconfigured for enabling a respective dental model 100A, or 100B of partor of the full respective dental arch (upper or lower) to be mountedthereonto, and comprise engagement prongs 663 and abutment surface 667similar to engagement prongs 70 and abutment surface 48, respectively,of the embodiment of FIG. 6, mutatis mutandis. Spacer portions 636rigidly interconnect the respective base part 631 to the respectivemodel mounting arrangement 664 such as to provide a known spatialrelationship between the axis 643 on the one hand, and prongs 663 andabutment surface 667 on the other hand, in order that the respectivemodels 100A and 100B may be designed and manufactured in a manner suchthat the mounting blocks 131A, 131B can engage with the respectivemounting arrangement 664 to provide the required spatial relationshipbetween the tooth models and the axis 643, in six degrees of freedom,for the particular articulator 640.

For any particular articulator design, a number of sets of adaptors 630,640 may be provided, each set providing a different spatial relationshipbetween axis 643, and prongs 663 and abutment surface 667, to enableaccommodation of dental models of patients having widely varyinganatomies to be used with the same articulator. For example, two sets ofadaptors may be provided for use with an articulator 640—one set for usewith models of adult teeth, and the other for use with models ofchildren's teeth. When designing models 100A, 100B for use with aparticular articulator 640, the designer may design the models assumingthat one set of adaptors is to be used thereof. If the resulting virtualmodels are unsatisfactory, for example from a mechanical integrity pointof view, the models may be designed again, using a different set ofadaptors, and the process repeated until an acceptable combination ofadaptors and teeth model is obtained. Optionally, such an iterativeprocess may be carried out automatically, once the virtual model of theteeth has been established.

In alternative variations of these embodiments, any other suitablefacebow apparatus may be used for engaging to a patient in therespective normal manner, and this may be followed by scanning portionsof the facebow apparatus as necessary to obtain a second virtual modelwherein the positions of the parameter of interest, including the jawhinge axis and the midsagittal plane, and to enable a reconstruction ofat least a portion of the teeth that is coupled (also referred tointerchangeably herein as “optically coupled” or “visually coupled”)with an identifiable part of the dental surfaces of the patient. Thisenables steps 450 and 470 to be carried out in a similar manner to thatdisclosed above regarding the facebow apparatus 100, mutatis mutandis.

One such alternative variation of the first embodiment is illustrated inFIGS. 15, 16, and 17 and is designated with the reference numeral 800.The facebow apparatus 800 comprises a U-shaped facebow portion 810, anda bite fork portion 820, substantially similar to facebow portion 120and bite fork portion 140 of the first embodiment, mutatis mutandis,with the following differences. In the embodiment of FIGS. 15 and 16,the facebow portion 810 comprises a pair of L-shaped arms 813, eachhaving an ear canal insertion portion 829 at or close to a free end 811thereof for engagement to the ear canals of a patient. The ear canalinsertion portions 829 define an axis 828 through the ear canals of thepatient when they are engaged therein. The other ends 812 of arms 813are pivotably connected together about axis 839 at coupling 840 (shownas a dotted line), onto which bite fork portion 820 is coupled,providing the bite fork portion 820 with at least three degrees offreedom with respect to the facebow portion 810. Axis 839 is generallyperpendicular to a sagittal plane of the patient. The first degree offreedom is rotation of the bite fork portion 820 with respect to thefacebow portion 810 about axis 839.

Facebow portion 810 also comprises near ends 812 planar portions 830which have a characteristic planar surface 815 of a particular planshape—for example a rectangle as illustrated—and the position andorientation of the planar portions 830 with respect to the ear canalinsertion portions 829 is known.

Bite fork portion 820 comprises a bite plate 832 having an upper surface833 which in use abuts against the cusp tips of the dental structure 850of the maxillary arch of the patient, or at a least a portion thereof,and a support arm 834 at a distal end thereof rigidly attached to thebite plate 832. The support arm 834 is slidingly received in thecoupling 840 along axis 849 (substantially orthogonal to axis 839), andthe relative position of the arm 834, and thus of the bite fork portion820, with respect to the coupling 840 may be selectively adjusted.Furthermore, the arm 834 is configured for being selectively rotatedwith respect to the coupling 840 about axis 849. Thus, the second andthird degrees of freedom are rotation and translation of the bite forkportion 820 with respect to the facebow portion 810 about and along axis849, respectively.

Each arm 813 further optionally comprises a pointer 814 controllablyslidable along the length thereof, and for reversibly locking at anydesired location thereon, and the pointer can be manipulated to bebrought into registry with the hinge axis or TMJ of the patient's jawwhen the portions 829 are engaged with the patient's ears.

All the dimensions of the apparatus 800 are known (and thus the relativespatial disposition between the coupling 840 and the facebow portion810, and in particular the ear canal insertion portions 829 is thusfixed), except for the relative spatial disposition between the bitefork portion 820 and the facebow portion 810, since relative movementbetween the two is permitted via the coupling, and their relativespatial disposition is fixed in a manner essentially determined by theanatomy of the patient.

In use, the apparatus 800 is mounted to the patient as follows. Thefacebow portion 810 is mounted onto the patient by engaging the earcanal insertion portions 829 in the respective ear canals of thepatient. Then, the bite fork portion 820 is engaged with at least theupper dental arch of the patient—in practice, the bite plate 832 isabutted against at least the upper dental arch, by rotating the bitefork portion 820 about axis 839 and/or 849 and/or by translating thebite fork portion 820 along axis 849 as required for such abutment. Ofcourse, the facebow portion 810 may be tilted with respect to the earcanals as required to enable the engagement of the bite fork portionwith the dental structure 850. Optionally, the pointers 814 may bealigned with the position of the jaw hinge axis H or TMJ, and thisposition may have been previously marked on the skin of the patient bythe practitioner in a manner, as is well known in the art, for example.

With the position and orientation of the bite fork portion 820 fixedwith respect to the facebow portion 810, and this spatial orientationmay be locked via a suitable clamp member (not shown), the followingsteps are conducted, referring to FIG. 16.

Zone A1 is scanned using scanner 250, including part of the dentition850 coupled with the bite plate 832, and a virtual model V1 is generatedof the scanned zone A1, for example as illustrated in FIG. 18. Thisvirtual model V1 comprises one part P1 that is representative of thedental structure 850, and another part P2 that is representative of thebite fork portion 820.

A second zone A2 is scanned, including the coupling 840 and at leastpart of the facebow portion 810 and part of the bite fork portion 820 inthe vicinity of the coupling 840 to provide another virtual model V2which shows the position and orientation between the coupling 840 andthe facebow portion 810, and the position and orientation between thecoupling 840 and the arm 834.

Since the geometry of the bite fork portion 820 is known, it is thenpossible to refer both virtual models V1 and V2 to the same coordinatesystem. Part P2 can be analysed so that the position and orientation ofP1 with respect to P2, and thus to the facebow portion 810 can bedetermined. Since the relative position of the ear canal insertionportions 829 with respect to the facebow portion 810 is also known, thusthe position and orientation of P1 with respect to axis 828 through theear canals can be determined.

A virtual model of the patient's dentition including the dentalstructure 850 can then be registered with respect to P1, and thus theposition and orientation of the axis 829, which is a body reference ofinterest, can be determined with respect to the virtual model of thepatient's dentition in a common coordinate system. For example, dentalstructure 850 may be the cusps of some of the upper teeth of thepatient, as observed via the open mouth of the patient, while theaforesaid virtual model of the patient's dentition may be the full upperdental arch that includes these cusps.

Optionally, another scan may be provided of a zone A3 including themarkers 814, such that the position and orientation of the markers withrespect to the arms 813 may be determined, and thus the position andorientation of the TMJ, which is also a body reference of interest, canbe determined with respect to the virtual model of the patient'sdentition in a common coordinate system.

Referring to FIG. 17, the bite plate 832 may optionally comprise indiciaor other markings, for example a series of intersecting lines 831engraved therein, protruding therefrom or marked thereon, which areeasily identifiable in the virtual model V1 and thus assist inidentifying the relative spatial position between P1 and P2, as well asfacilitating the step of combining the virtual models V1 and V2 to thesame coordinate system.

Another alternative variation of the first embodiment is illustrated inFIG. 19 and is designated with the reference numeral 900. The geometricstructure is in the form of facebow apparatus 900, which comprises aU-shaped facebow portion 910, and a bite fork portion 920, substantiallysimilar to facebow portion and bite fork portion of the first embodimentand variations thereof, mutatis mutandis, with the followingdifferences. In the embodiment of FIG. 18, the facebow portion 910comprises a pair of arms 913 joined to a base 919 to form a U, each arm913 having an ear canal insertion portion 929 at or close to a free end911 thereof for engagement to the ear canals of a patient. The ear canalinsertion portions 929 define an axis 928 through the ear canals of thepatient when they are engaged therein.

A downwardly depending arm 935 is centrally connected to the base 919,and comprises at its lower end 936 a coupling 940 onto which bite forkportion 920 is coupled, providing the bite fork portion 920 with atleast two degrees of freedom with respect to the facebow portion 910.

All the dimensions of the apparatus 900 are known (and thus the relativespatial disposition between the coupling 940 and the facebow portion910, and in particular the ear canal insertion portions 929 is thusfixed), except for the relative spatial disposition between the bitefork portion 920 and the facebow portion 910, since relative movementbetween the two is permitted via the coupling, and their relativespatial disposition is fixed in a manner essentially determined by theanatomy of the patient.

Bite fork portion 920 is similar to the bite fork portion 820 of theembodiment of FIGS. 15 to 18, mutatis mutandis, and comprises a biteplate 932 having an upper surface 933 which in use abuts against thecusp tips of the dental structure 850 of the maxillary arch of thepatient, or at a least a portion thereof, and a support arm 934 at adistal end thereof rigidly attached to the bite plate 932. The supportarm 934 is slidingly received in the coupling 940 along axis 949(substantially along the midsagittal plane or a sagittal plane of thepatient), and the relative position of the arm 934, and thus of the bitefork portion 920, with respect to the coupling 940 may be selectivelyadjusted. Furthermore, the arm 934 is configured for being selectivelyrotated with respect to the coupling 940 about axis 949. Thus, theaforesaid at least two degrees of freedom include rotation andtranslation of the bite fork portion 920 with respect to the facebowportion 910 about and along axis 949, respectively.

Each arm 913 further optionally comprises a pointer 914 controllablyslidable along the length thereof, and for reversibly locking at anydesired location thereon, and the pointer can be manipulated to bebrought into registry with the hinge axis or TMJ of the patient's jawwhen the portions 929 are engaged with the patient's ears.

In use, the apparatus 900 is mounted to the patient as follows. Thefacebow portion 910 is mounted onto the patient by engaging the earcanal insertion portions 929 in the respective ear canals of thepatient. Then, the bite fork portion 920 is engaged with at least theupper dental arch of the patient—in practice, the bite plate 932 isabutted against at least the upper dental arch, by rotating the bitefork portion 920 about axis 949 and/or by translating the bite forkportion 920 along axis 949 with respect to coupling 940 as required forsuch abutment. Of course, the facebow portion 910 (including the wholeapparatus 900) may be tilted with respect to the ear canals as requiredto enable the engagement of the bite fork portion with the dentalstructure 850. Optionally, the pointers 914 may be aligned with theposition of the jaw hinge axis H or TMJ, and this position may have beenpreviously marked on the skin of the patient by the practitioner in amanner, as is well known in the art, for example.

With the position and orientation of the bite fork portion 920 fixedwith respect to the facebow portion 910, and this spatial orientationmay be locked via clamp member 941, the following steps are conducted.Zone B1 is scanned using scanner 250, including part of the dentition850 coupled with the bite plate 932, and a virtual model V1′ isgenerated of the scanned zone B1. This virtual model V1′ comprises onepart P1′ that is representative of the dental structure 850, and anotherpart P2′ that is representative of the bite fork portion 920.

A second zone B2 is scanned, including the coupling 940 and part of thebite fork portion 920 in the vicinity of the coupling 940 to provideanother virtual model V2′ which enables the position and orientationbetween the arm 934 (and thus the bite fork portion 920) and coupling940 (and thus the facebow portion 910) to be determined.

Since the geometry of the bite fork portion 920 is known, it is thenpossible to refer both virtual models V1′ and V2′ to the same coordinatesystem, as with other variations of this embodiment. Part P2′ can beanalysed so that the position and orientation of P1′ with respect toP2′, and thus to the facebow portion 910 can be determined, since thegeometry of the arm 935, coupling 940, base 919 and arms 913 is alsoknown. Since the relative position of the ear canal insertion portions929 with respect to the facebow portion 910 is also known, thus theposition and orientation of P1′ with respect to axis 929 through the earcanals can be determined.

A virtual model of the patient's dentition including the dentalstructure 850 can then be registered with respect to P1′, and thus theposition and orientation of the axis 929, which is a body reference ofinterest, can be determined with respect to the virtual model of thepatient's dentition in a common coordinate system. For example, dentalstructure 850 may be the cusps of some of the upper teeth of thepatient, as observed via the open mouth of the patient, while theaforesaid virtual model of the patient's dentition may be the full upperdental arch that includes these cusps.

Optionally, another scan may be provided of a zone B3 including themarkers 914, such that the position and orientation of the markers withrespect to the arms 913 may be determined, and thus the position andorientation of the TMJ, which is also a body reference of interest, canbe determined with respect to the virtual model of the patient'sdentition in a common coordinate system.

As with bite plate 832, mutatis mutandis, bite plate 932 may also haveindicia or other markings, to assist in identifying the relative spatialposition between P1′ and P2′, as well as facilitating the step ofcombining the virtual models V1′ and V2′ to the same coordinate system.

Regarding the embodiments of FIGS. 2 to 4, 15 to 19, scans of zones ofthe respective apparatus that are not coupled with the respective dentalstructure may be performed while the respective apparatus is engagedwith the patient, or after the removal of the respective apparatus fromthe patient—for example, regarding the embodiment of FIG. 19, zones B2and B3 can be made with the apparatus engaged or disengaged from thepatient. However, the scan of the zone including the coupling betweenthe tooth structure and apparatus, for example zone B for the embodimentof FIG. 19, must be done while the respective apparatus is engaged withthe patient.

Nevertheless, the above embodiments may be utilized in a slightly variedmanner to enable a virtual model representative of the coupling betweenthe dental structure and the apparatus to be obtained after theapparatus is disengaged from the patient.

Referring to FIG. 20, with respect to the embodiment of FIG. 19, thebite plate 932 comprises a layer of impressionable material 960. Such amaterial may be include materials routinely used in the art to obtainphysical impressions of the dentition, and which are subsequently usedin the art to cast therefrom stone or plaster models of the dentition,for example. In use, the patient abuts the bite plate 932 to the dentalstructure 850, and in doing so creates an impression 965 in the material960, corresponding to the contours and shape of the dental structure850. Of course, the remainder of the apparatus 900 is properly engagedto the patient, as described above, mutatis mutandis. Once the material960 has set, the apparatus may be disengaged and removed from thepatient, including the bite plate and material. Now, a scan of the biteplate 932 coupled to the impression 965 can be taken, and this willenable a virtual model to be generated, in which the position andorientation of dental structure with respect to the bite plate 932 canbe determined, since the part of the virtual model corresponding to theimpression 965 corresponds to the dental structure, and in fact avirtual model of the whole dentition may be registered with the virtualmodel corresponding to the impression 965. Thus, the virtual model ofthe dentition may be spatially related to a desired body reference suchas axis 928 or the TMJ as disclosed above, mutatis mutandis.

In a similar manner to the embodiment of FIG. 19, the embodiments ofFIGS. 2 to 4, 15 to 18 may be modified to include a layer of impressionmaterial and used in a similar manner, mutatis mutandis.

In a second embodiment of the invention, and referring again to FIGS. 2to 4, the bite fork portion 140 is provided as a separate andindependent tool that may be coupled to the oral cavity of the patientand scanned together therewith, in a similar manner as disclosed hereinfor the first embodiment of the facebow apparatus 100, mutatis mutandis,without the need to provide or use the full facebow apparatus 100,mutatis mutandis. Step 410 is as for the first embodiment, mutatismutandis, and in step 430, according to the second embodiment, thespatial parameter of interest is the position and orientation of theplane of the cusp tips with respect to the midsagittal plane, or atleast with respect to a sagittal plane, and this may be accomplished ina similar manner to determining the position of a vertical planeassociated with the vertical plate 144, in a similar manner to thatdisclosed above for the first embodiment, mutatis mutandis.Alternatively, the spatial parameter of interest may simply be thegenerally orientation of the teeth with respect to the midsagittalplane, or at least with respect to a sagittal plane. In any case, instep 450 according to the second embodiment, the first virtual model ofthe intraoral cavity that has already been obtained is then matched tothe dental surfaces scanned while coupled to the bite plate 142, and instep 470 according to the second embodiment, the spatial position andorientation of the sagittal or midsagittal plane with respect to thefirst virtual model is determined, being aligned with or at leastparallel to the vertical plate. In turn, this information, i.e., thespatial position and orientation of the sagittal or midsagittal planewith respect to the first virtual model, is determined, and may beuseful in planning, inter alia, a prosthodontic procedure, for example,in which one or more incisor prosthetics, including veneers for theincisors, may be designed to be aligned as close as possible to thesagittal plane, even if the cusp tip plane or the occlusal plane istilted to the right or the left of the midsagittal plane when thepatient is viewed from the front.

In alternative variations of the second embodiment, rather than the bitefork portion 140, any suitable rigid plate, strip, rod, or the like maybe aligned with the midsagittal plane of the patient, in close visualproximity to the intraoral cavity, so that a portion of the thusvertical plate is visually coupled to a portion of the teeth during ascanning thereof in step 430, sufficient for enabling reconstruction ofthe vertical surface of the plate and of enough of the dental surface toallow a match in step 450 with the first virtual model to be achieved.

In yet other variations of this embodiment, any suitable geometricalstructure, for example in the form of an artifact, may be coupled to aportion of the teeth during a scanning thereof in step 430, sufficientfor enabling reconstruction of the geometrical structure and of enoughof the dental structure to allow a match in step 450 with the firstvirtual model to be achieved. The geometrical structure can comprise anyshaped structure the shape of which provides information linking thegeometrical structure to the midsagittal plane of the patient directly,or indirectly via any other reference plane or axis of the head of thepatient.

For example, and referring to FIGS. 11 and 12, another variation of thesecond embodiment is illustrated, in which such a geometrical structure,designated with the reference numeral 700 comprises a first nosecircumscribing portion 710 in the form of a an isosceles triangle-shapedpiece of sheet material having a triangular shaped opening 712, theportion 710 having an upper vertex 714 between the two equal sides ofthe triangle, and lower base portion 716. A lower strip 720 of sheetmaterial is generally coplanar with portion 710 and projects downwardlyfrom the center of the base portion 716, in a direction generallyorthogonal thereto. An upper strip 730 of sheet material projectsupwardly from the vertex 714, in a direction generally parallel andaligned with respect to the lower strip 720. Each of the strips 720, 730optionally comprises a marking in the form of lines 722, 732 whichprovide light intensity and/or colour contrast with the rest of therespective strip. Lines 722 and 732 are in fixed geometricalrelationship with the outer surfaces 725, 735 of the respective strips720, 730, and the lines 722, 732 are aligned and parallel to oneanother, though in other variations of the embodiment of FIGS. 11 and 12other markings may be provided, or the lines may be non-aligned and/ornon-parallel to one another, or no lines or markings of any kind may beprovided.

Portion 710 is thus an interconnecting portion for interconnecting strip720 and 730.

In any case, in the embodiment of FIGS. 11 and 12, or variationsthereof, the strip 720, nose circumscribing portion 710 and strip 730are in a fixed and known geometrical relationship with respect to oneanother. In particular, the geometrical structure 700 is formed as anintegral piece from sheet material, though in variations of thisembodiment it may be made from several pieces joined together in anysuitable fashion. In this embodiment, the artifact is substantiallyrigid and is planar, for example about the Z-Y plane, though invariations thereof the artifact may be non-planar. In yet othervariations of this embodiment, the geometrical structure may besemi-rigid, for example allowing reversible bending or controlleddeformation about the Z-Y plane, though limited or no bending ordeformation being allowed along other planes, for example. In suchcases, the positions of the various portions of the geometricalstructure 700 are known, knowable or determinable, or alternatively, thevarious portions of the geometrical structure 700 are at leastidentifiable.

The opening 712 is configured for enabling the nose of a patient toprotrude therefrom while the portion 710, in particular the vertex 714and/or the base portion 716 are as close as possible to the intraoralcavity and nose bridge, respectively, of the patient.

At least the upper part of strip 730 comprises an adhesive patch 740, oralternatively may comprise an adhesive layer on the back thereof.

The geometrical structure 700 may be used as follows. The artifact 700is placed over the face of the patient such that the nose passes throughopening 712, and the strips 720, 730 are aligned with the midsagittalplane of the patient. In particular, the lines 722, 732 may be alignedwith the midsagittal plane. The spacing and alignment between the strips720, 730 facilitate alignment thereof with respect to the midsagittalplane. Then, the geometrical structure 700 is temporarily affixed to thepatient's head in this position by means of the adhesive patch 740,and/or by other means, for example additional adhesive tape, elasticbands, and so on. The patient's mouth should be open at leastsufficiently for enabling at least some of the dental surfaces to beviewed in proximity to and visually coupled with the lower strip 720and/or any other part of the geometrical structure 700. The visibledental surfaces are then scanned together with at least a portion of thelower strip 720 coupled therewith, this lower portion being sufficientto enable therefrom the position of the strip 720 itself, and thus theposition of the midsagittal plane. Thus, the lower strip 720 is in closevisual proximity to the intraoral cavity, so that a portion of the strip720, in particular a portion of line 722, is visually coupled to aportion of the teeth during a scanning thereof in step 430, sufficientfor enabling reconstruction of the strip 720 and line 722 (and thus ofthe position of the midsagittal plane), and of enough of the visibledental surface to allow a match in step 450 with the first virtual modelto be achieved.

In alternative variations of the embodiment of FIGS. 11 and 12, the nosecircumscribing portion may take any other suitable form, including, forexample a three-dimensional form such as a cup or the like to fit overthe nose of the patient.

In one particular variation of the embodiment of FIGS. 11 and 12,illustrated in FIGS. 13 and 14, the geometrical structure, hereindesignated 700′, comprises all the elements and features of theembodiment of FIGS. 11 and 12, and further comprises a left eyeencircling portion 760 and a right eye encircling portion 770 thatdefine openings 791 a and 791 b, respectively, that enable the eyes tobe seen therethrough and further facilitates alignment of the strip 720with the midsagittal plane by centering the portions 760 and 770 overthe respective eyes of the patient when the nose is protruding from theopening 712. The portions 760 and 770 thus comprise in this embodimentV-shaped or C-shaped strips of material connected to the portion 710, toform a frame 701, though any other suitable shape that facilitatescentering the artifact with respect to the eyes, and thus with respectto the midsagittal plane, may also be used. Optionally, target markings791 may be provided to facilitate centering of the geometrical structure700′ with respect to the eyes and/or the nose bridge of the patient. Inthis embodiment, the strip 730 is omitted, though in other variations ofthe embodiment, an upper strip may be provided. Furthermore, thegeometrical structure 700′ comprises a pair of side members 790 that actin a similar manner to the temple portions of eyeglasses, and each havea shaft 792 and bend 794 to fit over and rest against the ears of thepatient, and the opening 712 comprises a bridge 796 with opposednosepads 798 for resting over the bridge of the nose. Each shaft 792 isconnected to the respective portion 760, 770 via a hinge 793, forexample a film hinge, to enable the side members 790 to be pivotedbetween a flat configuration (for example, manufactured integrally withthe rest of the artifact from a sheet of material), a deployedconfiguration, for installing on a patient, for a folded configuration,for storage. Optionally, the openings 791 a, 791 b may comprise atransparent film of material, which further optionally may comprisemarkings 799 thereon to further facilitate centering the portions 760,770 on the eyes in a symmetrical manner. In alternative variations ofthe embodiment of FIGS. 13, 14, the side elements 790 may be replacedwith a head encircling elastic chord, for example, the ends of which arefixed one each to the respective sides 795 of the frame.

In use, the geometrical structure 700′ is placed over the face of thepatient such that the nose passes through opening 712, and the bridge796 sits over the nose bridge of the patient, and the elements 790 restover the respective ears of the patient, in a similar manner to fittingeyeglass frames on the face, mutatis mutandis. The geometrical structure700′ is manipulated until the eyes of the patient are centralized withinthe portions 760, 770, and strip 720, in particular line 722, are thennominally automatically aligned with the midsagittal plane of thepatient. The geometrical structure 700′ may optionally be furtheraffixed to the patient's head in this position by any suitable means,for example adhesive tape, elastic bands, and so on. The patient's mouthshould be open at least sufficiently for enabling at least some of thedental surfaces to be viewed in proximity to the lower strip 720 and/orany other part of the geometrical structure 700′. The visible dentalsurfaces are then scanned together with at least a portion of the lowerstrip 720, this lower portion being sufficient to enable therefrom theposition of the strip 720 itself, and thus the position of themidsagittal plane. Thus, the lower strip 720 is in close visualproximity to the intraoral cavity, so that a portion of the strip 720,in particular a portion of line 722, is visually coupled to a portion ofthe teeth during a scanning thereof in step 430, sufficient for enablingreconstruction of the strip 720 and line 722, and of enough of thevisible dental surface to allow a match in step 450 with the firstvirtual model to be achieved.

Thus, in the embodiments of FIGS. 11 to 14, the geometrical structure ineach case (also referred to herein as an apparatus) comprises a firstpart that is alignable with a body reference including a reference axisor plane of choice of the patient, for example a midsagittal plane, anda second part that is in proximity to the dental structure of interestsuch as to be optically coupled thereto when scanned. The first part andthe second part are in a fixed or determinable geometric and/or spatialrelationship with respect to one another. Thus, the position of theaforesaid body reference, reference axis or reference plane of thepatient can be defined with respect to the second part, the spatialrelationship between the second part and the dental structure can bedetermined by scanning the two, so that the disposition of the dentalstructure with respect to the body reference, reference axis or planecan be determined.

It is to be noted that the embodiments of FIGS. 11 to 14 can bemodified, mutatis mutandis, to provide alignment information of thescanned dental surfaces with respect to any other body referenceincluding a reference plane or axis of the patient, by providing therelative disposition of such a body reference, reference plane or axiswith respect to the lower strip 720, for example. Furthermore, the strip720 may be replaced in alternative embodiments with a bar or othersuitable physical structure, for example, having a fixed or determinablegeometrical/spatial relationship with the upper strip 730 in the case ofthe embodiment of FIGS. 11, 12, or the frame 701 in the case of theembodiment of FIGS. 13, 14.

Furthermore, the embodiments of FIGS. 11 to 14 may be constructed from aformer cut or stamped from sheet material, for example cardboard orplastic sheet material, and may furthermore be made as low-cost itemssuitable for disposal after one use, or alternatively various uses witha single patient. Alternatively, the embodiments of FIGS. 11 to 14 maybe constructed from less inexpensive materials, for example metals, formultiple use, and preferably capable of being sterilized, for examplevia autoclave, between uses, or between patients.

In yet other variations of this embodiment, the aforesaid geometricalstructure is coupled to the dental structure in an exclusively visualmanner, such as for example via visual markings on the face of thepatient, without the need for an external physical structure to bemounted to the patient visually coupled to the intra oral cavity. Forexample, a line may be drawn, printed or painted onto the face of thepatient along the midsagittal plane, for example from the nose to theupper lip, lower lip, or chin, and is thus visually coupled to a portionof the teeth during a scanning thereof in step 430. The colour,contrast, thickness of the line constitutes the geometrical structure,and this together with the part of the dental structure in the vicinitythereof, are scanned in this step, sufficient for enablingreconstruction of the geometrical structure and of enough of the dentalstructure to allow a match in step 450 with the first virtual model tobe achieved. Alternatively, the marking may comprise any shaped symbolor geometric segment the shape of which provides information linking themarking to the midsagittal plane of the patient directly, or indirectlyvia any other reference plane or axis of the head of the patient.

In a third embodiment of the invention, in step 430 external tissuestructures, not included in the intraoral cavity, may be scanned, whilevisually coupled to at least a portion of the dental surfaces of thepatient. For example, and referring to FIG. 8(b), the lips, or at leastthe upper lip 380 of the patient is scanned together with part of thedental structure 385 visually coupled therewith, and a second virtualmodel of the lip 380 and dental structure 385 is reconstructed. The lipsmay be in a smiling position when the scan is taken. Another scan istaken to establish the first virtual model of the dental surfaces of theintraoral cavity, which also include representations of the same dentalstructure 385 that appear in the scan illustrated in FIG. 8(b), as wellas a number of incisor teeth 386 which need crowns. According to thisembodiment, the first and second virtual models are combined byregistering the respective parts thereof corresponding to common dentalstructure 385, and the prostheses 388, marked in broken lines, can bedesigned in a manner to be compatible with the lip 380. For example, theprostheses may be designed such as to align the interproximal line 389between them with the midsagittal plane 383, the position of which maybe determined by studying the morphology of the lip, and/or the cusps387 may be aligned with an imaginary arc 381 that follows the contour ofthe lower edge 382 of the lip 380, substantially irrespective of theposition of the respective preparation or stumps of the teeth 386 ortheir root structures. According to this embodiment, the designer taskof designing the prostheses for the anterior teeth to match the smile ofthe patient is greatly facilitated. The arc 381 may be an approximationto the smile line of the patient, for example.

It is to be noted that the computer system in which the virtual modelsare created and manipulated according to the invention does notnecessarily need to be located in the same geographical location as thescanner and patient. Thus, while the scanning of the patient is usuallydone at a dental clinic by the dentist or other dental practitioner, thedental clinic may instead or additionally be linked to one or moredental labs, and possibly also to a dental service center via acommunication means or network such as for example the Internet or othersuitable communications medium such as an intranet, local accessnetwork, public switched telephone network, cable network, satellitecommunication system, and the like. Additionally or alternatively, thecommunication means may include postal or courier services, the databeing communicated via a transportable medium such as an optical disc,magnetic disc and so on. In any case, once the second virtual model iscreated and matched with the first virtual model, the physical dentalmodel, and other dental procedures not carried out on the actualpatient, may be carried out by the dental lab which receives therequired data generated by the method 400 via the communications means.The dental service center may be used for manufacturing dental hardwarethat requires a very high degree of precision, for example innersurfaces of prostheses that are required to match external surfaces ofcopings, and possibly also the copings themselves.

According to a particular embodiment of the invention, the followingsteps are performed:

-   -   (a) a virtual impression of teeth is taken at a dental office,        i.e., a digitized model (virtual model) of the patient's teeth        is created.    -   (b) The patient bites onto the bite fork of facebow apparatus        100.    -   (c) The dental practitioner aligns the facebow apparatus with        the patient's face (longitudinal direction).    -   (d) The dental practitioner scans to provide the spatial        relationship between the facebow apparatus and the patient's        teeth.    -   (e) The scan data is transmitted or otherwise sent to a modeling        center for interpretation, and where necessary for virtual        ditching to provide virtual modeling of dental surfaces that are        obscured during scanning by either soft tissues and/or saliva,        debris etc., for example as disclosed in WO 2007/010524 to the        present Assignee and the contents of this reference are        incorporated herein in their entirety.    -   (f) The virtual model of the scanned data is displayed in the        correct orientation with respect to the patient facial features        or reference axes/planes (patient specific features).    -   (g) The virtual model is sent to the dental lab for approval.    -   (h) The lab approves the case, and sends the approval (or an        updated interpretation of the model) to a production center,        which manufactures a physical model of the teeth with features        that will enable the models to be mounted onto an articulator in        the required relationship with respect to the articulator hinge        axis. The models may be made by CNC machining or rapid        prototyping, for example.    -   (i) The dental lab designs the required prosthesis, coping, and        so on based on the model, and taking into account the patient        specific features.    -   (j) The physical model is sent to the lab and mated with the        prosthesis and/or coping that was produced in the lap for final        verification and esthetics building.    -   (k) The prosthesis and/or coping is sent to the dental        practitioner for implantation to the patient.

In the method claims that follow, alphanumeric characters and Romannumerals used to designate claim steps are provided for convenience onlyand do not imply any particular order of performing the steps.

Finally, it should be noted that the word “comprising” as usedthroughout the appended claims is to be interpreted to mean “includingbut not limited to”.

While there has been shown and disclosed example embodiments inaccordance with the invention, it will be appreciated that many changesmay be made therein without departing from the spirit of the invention.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. A method for providing a spatial relationship ofa dental structure of a patient with respect to a facial feature of thepatient, comprising: optically scanning, in a first optical scanningoperation, an externally visible portion of teeth of the patient inocclusion to produce a first model, the first model including spatialrelationship information that spatially relates the externally visibleportion of the teeth with a facial feature of the patient; opticallyscanning, in a second optical scanning operation, the teeth of thepatient to produce a second model, the second model including theexternally visible portion of the teeth scanned in the first opticalscanning operation and second portions of the teeth of the patient notscanned in the first optical scanning operation, the second portions ofthe teeth including portions not externally visible during the firstoptical scanning operation; aligning the externally visible portion ofthe teeth in the first model with the externally visible portion of theteeth in the second model; associating the spatial relationshipinformation of the first model with the second model so that the secondportions of the teeth of the patient are spatially related with thefacial feature; outputting the second model of the teeth of the patientwith the spatial relationship information; and generating a dentaltreatment using the second model of the teeth with the spatialrelationship information.
 2. The method of claim 1, wherein the firstoptical scanning operation and the second optical scanning operation areperformed with an intraoral scanner.
 3. The method of claim 1, whereinthe spatial relationship information that spatially relates theexternally visible portion of the teeth with the facial feature of thepatient is provided by an alignment apparatus coupled to the teeth andwherein the first optical scanning operation captures the dentalstructure of the alignment apparatus.
 4. The method of claim 3, whereinthe alignment apparatus occludes the second portions of the teeth of thepatient in the second model.
 5. The method of claim 2, wherein the firstoptical scanning operation includes scanning external to an oral cavityof the patient.
 6. The method of claim 5, wherein the second opticalscanning operation is an intraoral scanning operation.
 7. The method ofclaim 1, wherein the spatial relationship is a three-dimensional spatialrelationship.
 8. The method of claim 4, wherein the alignment apparatuscomprises a facebow apparatus structurally configured to align with thefacial feature.
 9. The method of claim 1, wherein the second opticalscanning operation comprises capturing color data and three-dimensionaldata of the dental structure.
 10. The method of claim 1, furthercomprising determining a hinge axis of the patient's jaw based on thespatial relationship.
 11. A system for providing a spatial relationshipof a dental structure of a patient with respect to a facial feature ofthe patient, comprising: a processor operably coupled to anon-transitory computer readable storage medium comprising instructionsthat, when executed, cause the processor to: receive a first opticalscan of an externally visible portion of teeth of a patient in occlusionto produce a first model, the first model including spatial relationshipinformation that spatially relates the externally visible portion of theteeth with a facial feature of the patient; receive a second opticalscan of the teeth of the patient to produce a second model, the secondmodel including the externally visible portion of the teeth scanned inthe received first optical scan and second portions of the teeth of thepatient not scanned in the received first optical scan, the secondportions of the teeth including portions not externally visible duringthe first optical scan; align the externally visible portion of theteeth in the first model with the externally visible portion of theteeth in the second model; associate the spatial relationshipinformation of the first model with the second model so that the secondportions of the teeth of the patient are spatially related with thefacial feature; and output the second model of the teeth of the patientwith the spatial relationship information.
 12. The system of claim 11,wherein the first optical scan and the second optical scan are capturedwith an intraoral scanner.
 13. The system of claim 11, wherein thespatial relationship information that spatially relates the externallyvisible portion of the teeth with the facial feature of the patient isprovided by an alignment apparatus coupled to the teeth and wherein thefirst optical scan captures the dental structure of the alignmentapparatus.
 14. The system of claim 13, wherein the alignment apparatusoccludes the second portions of the teeth of the patient in the secondmodel.
 15. The system of claim 12, wherein the first optical scanincludes a scan external to an oral cavity of the patient.
 16. Thesystem of claim 15, wherein the second optical scan is an intraoralscanning operation.
 17. The system of claim 11, wherein the spatialrelationship is a three-dimensional spatial relationship.
 18. The systemof claim 14, wherein the alignment apparatus comprises a facebowapparatus structurally configured to align with the facial feature. 19.The system of claim 11, wherein the second optical scan comprises colordata and three-dimensional data of the dental structure.
 20. The systemof claim 11, wherein the processor operably coupled to thenon-transitory computer readable storage medium further comprisesinstructions that, when executed, further cause the processor todetermine a hinge axis of the patient's jaw based on the spatialrelationship.